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/*

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include 

#include 

#include "atomic.h"

#include "buffer_internal.h"

#include "common.h"

#include "mem.h"

AVBufferRef *av_buffer_create(uint8_t *data, int size,

                              void (*free)(void *opaque, uint8_t *data),

                              void *opaque, int flags)

{

    AVBufferRef *ref = NULL;

    AVBuffer    *buf = NULL;

    buf = av_mallocz(sizeof(*buf));

    if (!buf)

        return NULL;

    buf->data     = data;

    buf->size     = size;

    buf->free     = free ? free : av_buffer_default_free;

    buf->opaque   = opaque;

    buf->refcount = 1;

    if (flags & AV_BUFFER_FLAG_READONLY)

        buf->flags |= BUFFER_FLAG_READONLY;

    ref = av_mallocz(sizeof(*ref));

    if (!ref) {

        av_freep(&buf);

        return NULL;

    }

    ref->buffer = buf;

    ref->data   = data;

    ref->size   = size;

    return ref;

}

void av_buffer_default_free(void *opaque, uint8_t *data)

{

    av_free(data);

}

AVBufferRef *av_buffer_alloc(int size)

{

    AVBufferRef *ret = NULL;

    uint8_t    *data = NULL;

    data = av_malloc(size);

    if (!data)

        return NULL;

    ret = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);

    if (!ret)

        av_freep(&data);

    return ret;

}

AVBufferRef *av_buffer_allocz(int size)

{

    AVBufferRef *ret = av_buffer_alloc(size);

    if (!ret)

        return NULL;

    memset(ret->data, 0, size);

    return ret;

}

AVBufferRef *av_buffer_ref(AVBufferRef *buf)

{

    AVBufferRef *ret = av_mallocz(sizeof(*ret));

    if (!ret)

        return NULL;

    *ret = *buf;

    avpriv_atomic_int_add_and_fetch(&buf->buffer->refcount, 1);

    return ret;

}

void av_buffer_unref(AVBufferRef **buf)

{

    AVBuffer *b;

    if (!buf || !*buf)

        return;

    b = (*buf)->buffer;

    av_freep(buf);

    if (!avpriv_atomic_int_add_and_fetch(&b->refcount, -1)) {

        b->free(b->opaque, b->data);

        av_freep(&b);

    }

}

int av_buffer_is_writable(const AVBufferRef *buf)

{

    if (buf->buffer->flags & AV_BUFFER_FLAG_READONLY)

        return 0;

    return avpriv_atomic_int_get(&buf->buffer->refcount) == 1;

}

void *av_buffer_get_opaque(const AVBufferRef *buf)

{

    return buf->buffer->opaque;

}

int av_buffer_get_ref_count(const AVBufferRef *buf)

{

    return buf->buffer->refcount;

}

int av_buffer_make_writable(AVBufferRef **pbuf)

{

    AVBufferRef *newbuf, *buf = *pbuf;

    if (av_buffer_is_writable(buf))

        return 0;

    newbuf = av_buffer_alloc(buf->size);

    if (!newbuf)

        return AVERROR(ENOMEM);

    memcpy(newbuf->data, buf->data, buf->size);

    av_buffer_unref(pbuf);

    *pbuf = newbuf;

    return 0;

}

int av_buffer_realloc(AVBufferRef **pbuf, int size)

{

    AVBufferRef *buf = *pbuf;

    uint8_t *tmp;

    if (!buf) {

        /* allocate a new buffer with av_realloc(), so it will be reallocatable

         * later */

        uint8_t *data = av_realloc(NULL, size);

        if (!data)

            return AVERROR(ENOMEM);

        buf = av_buffer_create(data, size, av_buffer_default_free, NULL, 0);

        if (!buf) {

            av_freep(&data);

            return AVERROR(ENOMEM);

        }

        buf->buffer->flags |= BUFFER_FLAG_REALLOCATABLE;

        *pbuf = buf;

        return 0;

    } else if (buf->size == size)

        return 0;

    if (!(buf->buffer->flags & BUFFER_FLAG_REALLOCATABLE) ||

        !av_buffer_is_writable(buf)) {

        /* cannot realloc, allocate a new reallocable buffer and copy data */

        AVBufferRef *new = NULL;

        av_buffer_realloc(&new, size);

        if (!new)

            return AVERROR(ENOMEM);

        memcpy(new->data, buf->data, FFMIN(size, buf->size));

        av_buffer_unref(pbuf);

        *pbuf = new;

        return 0;

    }

    tmp = av_realloc(buf->buffer->data, size);

    if (!tmp)

        return AVERROR(ENOMEM);

    buf->buffer->data = buf->data = tmp;

    buf->buffer->size = buf->size = size;

    return 0;

}

AVBufferPool *av_buffer_pool_init(int size, AVBufferRef* (*alloc)(int size))

{

    AVBufferPool *pool = av_mallocz(sizeof(*pool));

    if (!pool)

        return NULL;

    pool->size     = size;

    pool->alloc    = alloc ? alloc : av_buffer_alloc;

    avpriv_atomic_int_set(&pool->refcount, 1);

    return pool;

}

/*

 * This function gets called when the pool has been uninited and

 * all the buffers returned to it.

 */

static void buffer_pool_free(AVBufferPool *pool)

{

    while (pool->pool) {

        BufferPoolEntry *buf = pool->pool;

        pool->pool = buf->next;

        buf->free(buf->opaque, buf->data);

        av_freep(&buf);

    }

    av_freep(&pool);

}

void av_buffer_pool_uninit(AVBufferPool **ppool)

{

    AVBufferPool *pool;

    if (!ppool || !*ppool)

        return;

    pool   = *ppool;

    *ppool = NULL;

    if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))

        buffer_pool_free(pool);

}

/* remove the whole buffer list from the pool and return it */

static BufferPoolEntry *get_pool(AVBufferPool *pool)

{

    BufferPoolEntry *cur = *(void * volatile *)&pool->pool, *last = NULL;

    while (cur != last) {

        last = cur;

        cur = avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, last, NULL);

        if (!cur)

            return NULL;

    }

    return cur;

}

static void add_to_pool(BufferPoolEntry *buf)

{

    AVBufferPool *pool;

    BufferPoolEntry *cur, *end = buf;

    if (!buf)

        return;

    pool = buf->pool;

    while (end->next)

        end = end->next;

    while (avpriv_atomic_ptr_cas((void * volatile *)&pool->pool, NULL, buf)) {

        /* pool is not empty, retrieve it and append it to our list */

        cur = get_pool(pool);

        end->next = cur;

        while (end->next)

            end = end->next;

    }

}

static void pool_release_buffer(void *opaque, uint8_t *data)

{

    BufferPoolEntry *buf = opaque;

    AVBufferPool *pool = buf->pool;

    if(CONFIG_MEMORY_POISONING)

        memset(buf->data, FF_MEMORY_POISON, pool->size);

    add_to_pool(buf);

    if (!avpriv_atomic_int_add_and_fetch(&pool->refcount, -1))

        buffer_pool_free(pool);

}

/* allocate a new buffer and override its free() callback so that

 * it is returned to the pool on free */

static AVBufferRef *pool_alloc_buffer(AVBufferPool *pool)

{

    BufferPoolEntry *buf;

    AVBufferRef     *ret;

    ret = pool->alloc(pool->size);

    if (!ret)

        return NULL;

    buf = av_mallocz(sizeof(*buf));

    if (!buf) {

        av_buffer_unref(&ret);

        return NULL;

    }

    buf->data   = ret->buffer->data;

    buf->opaque = ret->buffer->opaque;

    buf->free   = ret->buffer->free;

    buf->pool   = pool;

    ret->buffer->opaque = buf;

    ret->buffer->free   = pool_release_buffer;

    avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);

    avpriv_atomic_int_add_and_fetch(&pool->nb_allocated, 1);

    return ret;

}

AVBufferRef *av_buffer_pool_get(AVBufferPool *pool)

{

    AVBufferRef *ret;

    BufferPoolEntry *buf;

    /* check whether the pool is empty */

    buf = get_pool(pool);

    if (!buf && pool->refcount <= pool->nb_allocated) {

        av_log(NULL, AV_LOG_DEBUG, "Pool race dectected, spining to avoid overallocation and eventual OOM\n");

        while (!buf && avpriv_atomic_int_get(&pool->refcount) <= avpriv_atomic_int_get(&pool->nb_allocated))

            buf = get_pool(pool);

    }

    if (!buf)

        return pool_alloc_buffer(pool);

    /* keep the first entry, return the rest of the list to the pool */

    add_to_pool(buf->next);

    buf->next = NULL;

    ret = av_buffer_create(buf->data, pool->size, pool_release_buffer,

                           buf, 0);

    if (!ret) {

        add_to_pool(buf);

        return NULL;

    }

    avpriv_atomic_int_add_and_fetch(&pool->refcount, 1);

    return ret;

}